staee



E. T. STARR. Dentists Chair.

No. 225,432.- .Patented Mar. 9, 1880;

" WITNESSES IJVVENTOR MPEFERS, PHQTO-UTNOGRAPNER, WASHINQTGN D C UNITED STATES PATENT OFFICE.

ELI T. STARR, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR T SAMUEL S. WHITE, OF SAME PLACE.

DENTISTS CHAIR.

SPECIFICATION forming part of Letters Patent No. 225,432, dated March 9, 11880.

' Application filed June 23, 1879.

To all whom it may concern:

Be it known that I, ELI T. STARR, of the city and county of Philadelphia, in the State of Pennsylvania, have invented certain new and useful Improvements in Dentists Chairs,

of which the following is a specification.

My invention relates to the class of chairs especially organized for the use of dentists, having a wide range of adjustment, whereby the patient when seated in the chair may be placed in the various positions necessary for the skillful performance of delicate dental operations.

The objects of my invention and the subject-m atter claimed will hereinafter specifically pose. The said chair-bodyis shown asconsist- 3o ing of a seat-frame, A, and a back frame or support. The back-frame is made in sections,

one, B, being fixed, while the other, B, is movable endwise relatively thereto and to the seat of the chair, the said fixed section B having a central and longitudinal slot, I), for the passage of a rearwardly-extended portion, b, of the sliding or adjustable section B. This extension I) constitutes the guide and support of the movable back-section, being provided with flanges or lips 12 which overlap the edges or project on each side of the guideslot 12, and thus prevent separation of the backsections, while not impeding or interfering with the adjustment of the one section upon the other, in order to lengthen or shorten the chair-back to accommodate persons of different size.

The vertically-adjustable backsection is locked from descending at any desired point 50 in its range of movement by means of a detent or toothed lever, D, pivoted thereto, the locking-tooth d of which engages with one of.

a series of ratchets, 6, formed in one edge or wall of the guide-slot in the fixed back-section. By raising the outer end of this lever its tooth is retracted from engagement with the teeth a, and the adjustable back-section is free to be moved up or down. When the lever is released the outer end is automatically and quickly depressed by its own weight, and the locking tooth thereon brought into engagement with the ratchet-teeth, thus locking the back-sections securely together.

It will be obvious, however, that various other devices may be employed to lock the back-sections together, if desired; but I prefer an automatic device.

A vertical socket or opening, f, is formed in the extension I) of the movable back-section for the reception of a vertically-adjustable straight cylindrical head-rest bar, E, said bar, in addition to its vertical adjustability, being also capable of a turning or swiveling movement in the socket.

The head-rest bar, it will be observed, is not only vertically adjustable in connection with the sliding back, but is also independently adjustable, and capable of being locked at any desired elevation relatively to said back by means of a clamp-screw, F, or other suitable looking or clamping device.

Upon the upper end of the head-rest bar is mounted a socketed split clamp, G, capable of moving endwise and of turning freelyaround the bar or at right angles to its longitudinal 8 5 axis, while connected with the clamp G, by means of a screw-bolt, H, is another or second and similar clamp, G, the said bolt being provided with a suitable handle, and passing through both the split clamps, so as to lock 9 them securely together by a single bolt or screw in a well-known way. This sectional I universal split-clamp joint arrangement is of well-known construction such, for instance, as that shown in Letters Patent No. 167,603, of September 14, 1875.

Through the socket of the clamp G is passed a straight cylindrical carrying-bar, I, capable of turning axially in the clamp, as well as of moving endwise backward and forward rela- 10o tively to the back and seat of the chair. This bar I has hinged or jointed upon its front end a head-rest pad or frame, J, of Well-known construction, the joint or hinge being shown in this instance as consisting of a curved or circular toothed plate,j. secured to the head-rest lrame, and pivoted atj in a suitable slot or fork formed in the end of the carrying-bar. The toothed plate is locked at any point desired in its range of movement around its pivot by a sliding spring-bolt located in a socket formed in the carrying bar in a well known way, whereby the head-rest may be adjusted or set at any angle desired relatively to the carryin g-bar, and independently of the adjustments of the bar itself.

From the above description it will be obvious that the head-rest is given a Wide range of movement in various directions relatively to the back and seat of the chair while capable of being clamped securely in any desired position by a single clamp-screwthat is to say, vertically, by the adjustability of the head-rest bar irrespective of the independent adjustment of the sliding back; horizontally, by the swiveling or turning of the head-rest bar in its socket and by the turning of the clamp G around said bar at right angles to its longitudinal axis; vertically, again, in the arc of a circle, by the capacity of the clamp-block G to swing or turn around the clamping bolt independently of the clamp-block G and at right angles to the movement of said clamp around the headrest bar; backward and forward, by the endwise movement of the carrying-bar in the clamp-block G, the bar being also capable of turning axially to throw the head-rest in different positions laterally, and independently of the carrying-bar, by means of the rocking joint or hinge connection, whereby the head-rest may be placed in any position desired relatively to the back and seat necessary for the ease and comfort of the patient, as well as to insure the skillful performance of dental operations.

enters said slot, and which is provided with a.

socket in rear of the back for the reception of a head-rest bar, a clamp to secure the said sections together, and a clamp to lock the head-rest bar in its socket.

2. The combination, substantially as hereinbefore set forth, of the vertically-adjustable;

chair-back, the vertically adjustable and turning or swiveling head-rest bar, the universal split-clamp joint, and the carrying-bar, upon one end of which the head-rest is mounted, movable endwise in said joint.

3. The combination, substantially as hereinbefore set forth, of the vertically-adjustable back or section, its socket, the head-rest bar fitted therein so as to be capable of independent vertical adjustment, the clamp acting to lock said head-rest bar in position, the universal clamp joint carried by said bar, the head-rest mounted upon one end of a carrying-bar which is adjustable backward and forward in the clamp-joint relatively to the back of the chair, and the independent rockin g joint between the head-rest and its carrying-bar.

In testimony whereof I have hereunto subscribed my name.

ELI T. STARR.

Witnesses:

WILLIAM H. GILBERT, WILLIAM METTENHEIMER. 

